Hydraulic assembly for adjustable ladder leg extension



June 3, 1952 R. J. ANDERSON HYDRAULIC ASSEMBLY FOR ADJUSTABLE LADDER LEG EXTENSION Filed April 9, 1951 2 SHEETS-SHEET l 6 my R E EW LM NH N & A w. J R

R H m P N Law A p w on ATTOQNEYS R. J. ANDERSON June 3, 1952 HYDRAULIC ASSEMBLY FOR ADJUSTABLE LADDER LEG EXTENSION 2 SHEETSSHEET 2 Filed April 9, 1951 RALPH J. ANDERSON INVENTOP HUEBNER, BEEHLER,

WORRE'L 8 HERZ/G ATTORNEYS Patented June 3, 1952 UNITED STATES PATENT;

HYDRAULIC ASSEMBLY FOR. ADJ USTABLE LADDER LEG EXTENSION Rall'ph' J.. Anae'rsbn, Tulare, cans, assi'gnor of one-halfito'Kenneth Billingsly, Tunis-cam.

AppIication'Apriw, 1951, Serial. No. 219,949

The present invention. relates tohydraulic sys environmentwithout departing from. thespiritor scope. of-..the:invention. .For descriptive: convene ience, however. vthei-nvention is illustrated in connection with, the support of ladders.

Various structureshave been provided; for utilizing. loads; supported on ladder legs. and the telescopically adjustable characteristics of such legs to accommodate uneven terrain. In my copending application identified above, is de scribed aload equalizing device which isalsosuitable for continuous compensation for elevationaLva-riations in a. support surface on which the ladderis rested; such as an undulating plate form and which also automatically equalizes the loadssupported on theladder legs during dis.--

placement of the ladder from initial position by thev imposition. of independently extended forces thereon. Although my previous loading equalizing device has proved successful it has been subject to. certain difliculties which the present invention seeks to overcome. 7

Originally; an excessive number of joints and connections were required to assemble the. device. A closeable feed opening was necessitated for purposes of supplying hydraulic fluid and for bleeding air therefrom. Every joint, connection,

closed opening and the like constitutes a poten tial area of leakage and increases production costs. requirements for close tolerances in associated elements and for skilled labor in the construction and assembly thereof. Further, the weight'and cost of materials utilized has been found to have been greater than necessary and substantial reductions therein. attainable by the practice of the present invention.

An object of the present invention is to provide an. improved load equalizing support means for laddersr and the like characterized by improved safety characteristics.

Anotherobject is to provide an improved. load.

equalizing S lifipfiit maiisfor ladders and tli like The production costs increase precise in predetermined attitude even when. reste f or-automaticalIy accommodating. uneven tens compensating.- for varied support conditions,

imizing opportunities for inadvrtentdi'splace j ment, and adaptedto. provide stationary support continuously or successively tipped, tilted, lated or otherwise displacedv support surface":

Another object is to. mini'mi nections inhydraulic systems.

Another object is-to. western-hydrated:

tems employing:- cylinders. and pli'iri' vious necessityf for filling. and-bleeding. openi gs;

Another obiectisto reduce theljco'st' off hydr'iauf lie systems by minimizing. requirements ments for skilled labor in. construction'and assembly. v

Another object is tov reduce. theTWeig-lit' of hydraulic controlsystems withoutfimfpairi he durability thereof and. conversely to; possi' ble a substantial increase indurability without" materially increasing the weight.

Another object is to.=provide. a h 7 p including a plunger telescopicallyassociated thv a tubular member which system is. automatically sealed by the slidable insertion of the plunger, into. the tubular. member and. which plunger. is

automatically locked; against; inadvertent ciation from the-tubular-member by such insertion.

A further object isto-provide improvedyelef ments and arrangements thereof ina device or the characterand for thepurposes. set forth; v Further objects and: advantages-will become apparent in the subsequent description in -t'he. specification.=

In the drawings: V Fig. l is a fragmentary front elevation 'of' a straight ladder supported on a hydraulicload equalizingysystem embodying. the principlesot the present invention. y

Fig. 2' is a; fragmentary rear elevation ot. the structure shown. in Fig. I.

Fig 3 is a fragmentary sidejelev'ation -ot the ladder and system shown in Fig." L taken-along;

line 3--3' of Fig.1.;

Fig. 4 is a fragmentary side-elevation? o f-v a'ladr" der leg; and. portion of the support systemrmounted thereonas taken outlined- 4 of Figl.

Fig. 5. is a horizontal: section taken on line of Fig. 1.. 7

Fig. 6 is a somewhat enlarged fragmentary.

vertical section of aload equalizing. supportsystem. embodying the principleslloi the Tpreseiit.

invention taken on Iine YG- B' of Fig. 5.

a un '11-? tolerances in associated elements. and.rec -1uirI-' yareunei Fig. 7 is a somewhat enlarged fragmentary side elevation of a tubular member and associated plunger.

Fig. 8 is a section taken on line 88 of Fig. 7.

Fig. 9 is a somewhat enlarged horizontal section illustrating a suitable valve structure optionally employed in the system.

Fig. 10 is a somewhat enlarged side elevation of the lower end of a plunger and associated foot positioned as employed to bring teeth thereof into downwardly disposed position.

Fig. 11 is an elevation of the structure shown in Fig. 10, as viewed in line I l-l I.

Fig. 12 is a side elevation of the structure shown in Fig. 10 as taken on line l2-|2.

Referring in greater detail to the drawings:

A straight ladder, fragmentarily illustrated in Figs. 1 to 4, is indicated generally at con-. sisting of a pair of elongated legs 2| intercon-' nected in fixed spaced relation by rungs exemplified at 22. As is well known, the legs may be in parallel, divergent, or convergent relation as desired. I

A load equalizing device for the legs 2| of the ladder 20 embodying the principles of the present invention is indicated generally at 25. The system is mounted on a pair of elongated angle brackets 26 for convenient attachment to the ladder legs or other objects to be supported. An

elongated cylindrical tubular member 21 is weldably or otherwise secured longitudinally in each of the brackets in the inner corners defined by the angular cross-sectional form thereof. The tubular members each provide an open end portion 28 endwardly extended from the bracket on which the tubular member is mounted and an opposite. closed end portion 29.

The ladder legs are notched, as shown at 30 in Fig. 4, to receive the tubular members 21 and the brackets bolted to the ladder legs, as at 3! in overlaying relation to the notches and tubular members. The notches further provide downwardly disposed shoulders 32 in rested relation on the closed ends 29 of the tubular members when the ladder is in an upwardly extended position.

The closed upper ends of the tubular members 21 are interconnected by a telescopically adjustable conduit 35 with the tubular members 21 in substantially parallel relation preferably of sufficiently malleable or flexible material to permit displacement of the brackets and tubular members from parallel relation subsequent to telescopicadjustment to accommodate ladders having divergent or convergent legs. The conduit 35 preferably is provided with a valve 36 therein intermediate the tubular members whereby fluid flow through the conduit may be restricted or precluded as well as opened for substantially unimpeded fluid flow therethrough. The valve preferably provides an operating handle 31 and may optionally incorporate a spring 38 resiliently to urge the valve into closed position.

The conduit is formed by welding outer tubes 40 to the upper end portions 29 of the tubular members 21 in communication with the hollow interiors thereof and laterally extended in juxtaposition inwardly from the legs 2 I on which their respective tubular members are mounted. Inner tubes 4| are weldably or otherwise secured to the valve 36 and oppositely extended therefrom telescopically into the inwardly extended ends of the outer tubes 40. The inwardly extended ends of the outer tubes 40 are counterbored at 42 and.

peripherally screw-threaded. An annular packing ring 43 is nested within the counterbore 42 and a slip nut 44 'slidably fitted to each of the inner tubes ll and screw-threadably mounted on their adjacent outer tubes 40 and tightened to provide fluid-tight interconnection of the pipes.

As a production convenience, the open end portion 28 of each tubular member 21 is formed by a hollow cylindrical extension mounted in each of the tubular members 21. The extension provides a sleeve 5| fitted to its respective tubular member and weldably secured thereto. The extension simply provides a production expedient for providing each of the ground members with a bore 52 of predetermined diameter at the ends of the tubular members and a counterbore 53 of appreciably greater diameter.

The sleeve 5| has an exterior surface 54 tightly fitted to the counterbore 53 and. an internal surface concentric thereto defining the bore 52. A slot 56 is formed radially through the sleeve longitudinally of the sleeve 5| from the inner end thereof providing a groove having a bottom defined by the inner surface of the counterbore portion 53.

laterally extended from its longitudinal slot 56. Each of the camways has an end adjacent to the slot formed through the sleeve and is extended laterally from the slot in progressively "decreased depth, eccentric to the longitudinal axes of the tubular member and sleeve on which it is formed to a point of disappearance at the inner surface of the sleeve in circumferentially spaced relation to the slot. The configuration of the camway and its relation to the slot are most clearly observable in Figs. 7 and 8.

It will be seen that the slot 56 has an outer end in spaced relation to the outer end of the sleeve 5|. An inwardly disposed annular groove 60 is provided in the sleeve adjacent to the open end portion thereof in spaced relation to the slot and has an annular packing member Bl, such as an O- ring packing of neoprene, rubber or other suitable material. An elongated plunger 64 is slidably fitted to each of the sleeves 5i and is extended therethrough into each sleeves respective tubular member 21 inwardly of the sleeve. A bore 65 is formed longitudinally of each of the plungers from the inner end thereof for a distance approximately that of the spacing of the outer ends of the slots 56 from the packing members 6!. An opening 66 is formed radially in the inner end of each of the plungers in communication with the bores 65. A detent 61 is mounted in each of the openings 66 for radial reciprocal movement and is urged radially outwardly by a leaf spring 68 inserted into the bore 65 and mounted in its detent as at 69 to limit outward movement therev of as well as to urge its detent radially outwardly to the fullest extent permitted by such connection. A bleeding port 10 is radially extended from the inner end portion of the bore 65 to the side of each plunger at a distance from its respective detent substantially equal to the spacing of the inner end of the slots 55 from the packing members 6| for purposes soon to become apparent.

The outer ends of the plungers 64 are provided with ball members 15. A substantially circular foot 16 having a downwardly disposed tread 11 of suitable slip resisting material is mounted for universal movement on each of the ball members by ball embracing cups 78. A serrated blade is rigidly mounted on each of the feet in radially extended position. As demonstrated in Figs. 10, 11, and 12, the feet may be turned up- Each of the sleeves is also 7 -provided with an inwardly disposed camway 60 "open endsupwardly extended.

wardlwsoias to. support: the ladder 211 ou the serrated: blade: 80; as; for resisting. slipping on ice and the like; Such tipping: is accommodated by a' slotiMf formed in the cup adapted to'rece'ive" a' portion: 82' of reduced" diameter" of its're'spective plunger 2 adjacent tot'he embraced ball mem-- ber I5. The slot is formed downwardly from the: upper edge oi the: cup a distance sufficient to permite tipping from the normal position shown in- Figs. 1 to 1 throughv an: annular distanceislightly greater than 90 to the: positions shown in Figs; I0, l l and 12in which. position the weight supportedon: the? serrated blade 80' serves. to maintain tne: foot in tlie upwardly tipped position for anti skid su port (Operation 'lfhefutility' of the device of the present'inven-' tionisbelievedfto be clearly apparent anfd is briefiyisu'mmarized at thispoiht. To install the attachme r'l't" 2 011 a ladder the legs 2I'l thereof" either -bef ore or after mounting the attachment 011 a ladder or other object to be supported, the tubular members 21 are positioned with their One of the plunge-rs 64 is shoved inwardly of its respective tu-- bular'member to the maximum amount of travel permitted. The other plunger is removed from its-respective tubular member in. an easily accomplished manner; To remove a'plunger it is simply drawn outwardly until the detent 61 rides against the inner end of the sleeve: 5| androtat'ed-until' the detent findsthe slot 55. Further outward movement of the'plunger draws the detentoutwardly along the slot. When the detent is aligned with the camway 6%; the plunger is rotated so that the, detent is caused totravel along the camwa' and thus is forced into retracted position in its respective plunger. When the detent is retracted sufficiently'to ride on the inner surface '52 of the sleeve, the plunger: is radially withdrawn from its tubular member and sleeve.

Oilor other suitable hydraulic fluid is poured into the'open end of the tubular member 21' from which the'plunger'fi'i has been removed-substantially fillingthe telescopic conduit 35, includ i'n'g'ithe valve 36'; and'both of the tubular members 2-1 not occupiedbythe remaining plunger. As the system is thus-filled with hydraulic fluid, the opposite plunger may be moved outwardly to facilitate filling as desired. When an adequate supply of fluid has been introduced, the removed plunger is simply slid inwardly through its respective sleeve and into its tubular member until the detent 66 passes the inner end of the sleeve 5| and snaps radially under the urging of the spring 68 to lock the plunger in tubular member engagement. To facilitate such insertion the inner ends of both plungers are preferably chamfered. It will be observed that the bore and the? port 10 of they inserted plunger 64. permits exhaust of excess fluid from the system incident to'insertion of the plunger and the emission of any air trapped therein.

As: the plunger is thrust inwardly it is rotatedand because of the described spacing of the" detent 6'6 and port 10 relative'to the outer end of the slot 56: and packing member 5!, the detent is thrust-radially of theplunger into the camway 60 or the outer end of the slot concurrently with movement of the port inwardly past the packing.v

member. Subsequently, the plunger is moved inwardly' of the slot beyond the sleeve 5| and the device is ready for use. It will be obvious that the simple insertion of the removed plunger seals the entire system for operation.

If during filling; air is trapped in the tubular member 21 opposite from that into which the fluid is introduced, the opposite plunger is moved 1 outwardly in its sleeve in the manner previouslydescribed a distance sufficient to uncover the port 10' and achieve the desired bleeding subsequent towhich the plunger is returned to position.

So preconditioned-for operation, the ladder 2'8 may beheld in any desired operable attitude on leveLsloped, or uneven terrain having. elevational variations within the limits of the combined telescopic'movements of the plungers in the tubular members and, with the valve 36 opened fora brief period, the weight of the ladder rested on thefeetl 6 automatically reciprocally adjusts the" plunger-tubular member relationships for the support'of substantially equal: loads on: thefeet.

When the valve is closed, the quantities ofhydraulicfluid. located on opposite sides. thereof precludes movement of: the plungers relative to their respective tubular members. In effect, this achieves av nearly instantaneous lengthening and 1 shortening of the legs 2| in response to ladder attitude'and type ofterrain on which the ladder is supported makingpossible the use of ladders on floors, stairway-s, curbs, and the like with equal: facility and prompt availability for use;

In some instances it is desirable to leave the valve 36 open during operation inwhich event the ladder is momentarily held in a working attitu'de' desi'redto permit accommodation of the plungers 64'in'th'e tubular membersZ'l to adjust tosupporting terrain and the ladder incli-ned ag ains't'a support wall or the like; With the valve open-,the upper end of; the ladder may be thrust laterally across-the supporting wall even while' supporting-'aworkman witha resultant automaticacc'ommodation of the plungers. in their tubular members; so that substantially equal weight is supported on' each of the feet. Obviously, in suchinstancesan operator supported on the ladder' and workingthe upper end thereof laterally of; a supporting wallmust be careful to avoid displacing his weight and that of the ladder so far laterally that friction of'the upper end of the leaderagainst" the Wallis inadequate to" preclude to 're'leasably lock the plunger for telescopic movement within its tubular member. 'The elimination of close tolerance requirements, the simplifying of the construction and the reduction of demands for skilled production labor has materially reduced production costs.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred method and embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and systems.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a hydraulic system, the combination of a tubular member having an open end, a sleeve having an inner and an outer surface mounted in the open end of the tubular member and having an inwardly disposed camway formed radially therein with an end in communication with the tubular member at the outer surface and inner end of the sleeve and an opposite end at the inner surface of the sleeve; a plunger extended through the sleeve into the tubular mem-. ber; and a spring-pressed detent radially extended from the plunger endwardly adjacent to the sleeve within the tubular member.

2. In a hydraulic control system, a cylinder having a longitudinal bore and a counterbore coaxial thereto, the cylinder having an inwardly disposed camway therein radially of the bore providing an end in communication with the counterbore having a bottom spaced from the axis of the bore and the counterbore a distance substantially equal to the radius of the counterbore and an opposite end having a bottom at the inner surface of the bore; a plunger slidably extended through the bore into the counterbore; and a spring-pressed detent laterally extended from the plunger within the counterbore.

3. In a hydraulic system, a member having an open-ended cylindrical opening therein, a sleeve mounted within the opening having an inner end provided with a slot longitudinally of the sleeve and an inwardly disposed camway having an end at the slot formed through the sleeve and laterally extended from the slot in progressively decreased depth to a point of disappearance at the inner surface of the sleeve in circumferentially spaced relation to the slot, a plunger extended inwardly through the sleeve axially thereof, and a spring-pressed detent laterally extended from the plunger inwardly of the sleeve.

4. In a hydraulic system, a cylinder having a bore longitudinally thereof, a sleeve mounted with an end within the bore of the cylinder having a slot longitudinally extended from its inner end and an inwardly disposed camway laterally extended from the slot formed eccentrically in the sleeve providing an end at the slot formed 8. radially through the sleeve and an opposite end at the inner surface of the sleeve, a plunger extended through the sleeve into the bore of the cylinder, and a spring-pressed detent laterally extended from the plunger inwardly of the sleeve receivable by the slot and camway and retractable into the plunger.

5. In a hydraulic control system, a cylinder having a bore longitudinally thereof and a coaxial counterbore, the bore having an open outer end and the counterbore having an inner end connected to the hydraulic system, an inwardly disposed groove being provided longitudinally of the cylinder from the inner end of the bore to a depth radially spaced from the axis of the bore and the counterbore substantially equal to the radius of the counterbore, and an inwardly disposed camway in the cylinder radially of the bore having an end at the groove of substantially the same depth as the groove and laterally extended therefrom in progressively decreasing depth to an opposite end at the inner surface of the bore; a plunger slidably extended through the bore into the counterbore; and a springpressed detent laterally extended from the plunger within the counterbore receivable by the groove and the camway and retractable into the ferentially removed from the slot; an annnular seal mounted within the sleeve adjacent to the outer end thereof and in spaced relation to the outer end of the slot; a plunger slidably extended through the seal; and a spring-pressed detent laterally extended from the inner end of the plunger, said plunger having a bore formed longitudinally from the inner end thereof and ported to the side of the plunger at a position spaced from the detent a distance substantially equal to the spacing of the outer end of the slot from the annular seal.

RALPH J. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,784,330 Bowers Dec. 9, 1930 2,231,252 Chesterman Feb. 11, 1941 2,449,920 Williams Sept. 21, 1948 2,552,941 Courtney May 15, 1951 

